Do the gases a worshiper feels during prayer, without hearing a sound, smelling an odor, or feeling air bubbles, nullify ablution, and must he interrupt the prayer and repeat ablution if he doubts whether wind has exited?

If it is merely a doubt, then the original state is the validity of the purity (tahara) and its not being invalidated. However, if there is a firm certainty that something has exited, then the purity is invalidated. One must be wary of obsessive whispers (waswas).